How to Insulate a Camper Van

About: I am an industrial designer, an interaction design researcher, a painter, a jeweller, a skier, a camping enthusiast, and I just love to make stuff!
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We just bought a new Mercedes Sprinter Van (2013, 144" with high roof) and are starting the conversion towards a winterized camper. We live in the Pacific Northwest and love to ski - our goal is to drive the sprinter around ski resorts and camp out in the parking lots, ready for the next day powder! The construction of this van is for us the start of uncountable adventures discovering the area around here. We are outdoors enthusiasts, love to do backpack camping and backcountry skiing, but we also want to have a bit more comfort, specifically in the winter. The first step was, of course, to insulate the walls, the floor and the ceiling of the van to keep the warmth in.

After reading multiple blogs and info sites about Sprinter and van conversions, we decided to use metallic bubble wrap, fiberglass insulation, and a plastic vapor barrier.

In total, it took us about 2 days (6-7 hours a day) with 2 to 4 people working on this to finish the insulation process. It cost us about 300$ for the materials (although we got the fiberglass insulation for free from a friend).

DISCLAIMER: This is the first van conversion we are doing, so this is certainly a process of trial and error! We tried to describe at every step the reasons why we made the choice materials we made, so hopefully you can see that we used common sense to design this process. I am an industrial designer and design researcher and my boyfriend is a landscape architect with some knowledge in wood working. We see this project as an experiment and as a wonderful place to try out some ideas about design, materials and fabrication.

Step 2: Tools

Safety first: Goggles, gloves, masks - particularly when working with the fiberglass insulation

Scissors

Exacto knife

Measuring tape

Screw driver and allen keys

Step 3: Preparation

The first step to insulate the van is to get it ready to accept the insulation.

Take out everything that is inside the van.

Remove the existing floor with a screw driver or allen key, depending on what attachments you have.

The result will be a metallic surface all around in the van.

Close off the driver's cabin with a plastic sheet to prevent having fiberglass all over the seats.

Set up a go pro if you want to do a timelapse video!

Now you are ready to start the hard work!

Step 4: Start With the Floor

We decided to start with the floor since once it is done, you can stand on it and work on the rest of the van.

Unroll the reflectix bubble wrap on the floor. Use the exacto or scissors to cut it to the appropriate length.

Secure the bubble wrap in place with the red tuct tape. You don't have to glue it all around, just enough to make sure it won't move once the flooring is put back on top.

Once you have done the middle piece, work around on the edges by placing the bubble wrap down and cutting it to size. The goal is to cover the whole floor before putting back the top on.

Put back the top onto the bubble wrap. Remember the order you took things appart. For us, we had to take out the piece closer to the front benches first and then remove the back one. So when placing them back, we started with the back piece and then the front one.

Where there are holes for the inserts to hold down the plywood, use an exacto knife to make a X shape hole. This way you can find the screw hole under and get ready to screw back the insert.

Place back the insert piece under the foil and then add the black metal piece.

Screw everything back in place!

Step 5: The Ceiling

The ceiling of the Sprinter van is separated by about 6 ribs of about 2 inches wide. In between each set of ribs, we placed durofoam foam boards to do the insulation. We decided to use this material for the ceiling since it is easy to place and can hold in place without too much trouble.

Measure the distance between the ribs for each casing.

Cut with an exacto knife the foam boards to the appropriate size.

Place the boards in place (ask a friend to help you!).

Use tuck tape to secure the boards to the ribs.

Step 6: The Walls: First Layer Is the Bubble Wrap

The most time consuming part of the insulation for the van was to work on the walls. We had to use 3 different materials all around, so this means a lot of time. The three layers are bubble wrap, fiberglass insulation and vapor barrier. The first layer, the bubble wrap, is to cut off the cold coming from the outside metal panel. The second layer, the fiberglass insulation, is used to create a larger thickness of air to keep the warmth inside and the cold outside. Finally, the third layer, the vapor barrier, is used to prevent the moisture coming from the inside of the van (think of melting snow from skis, stinky and wet feet, and boiling water and cooking) to go into the fiberglass insulation and create mould.

Remember, a van is not like a house, the materials don't breathe as much and moisture can really be a problem inside. (We did not use the vapor barrier on the ceiling or floor since there are almost no risk of having mould on the bubble wrap itself or on the durofoam on the ceiling).

Unroll a part of the bubble wrap, measure approximately how much you will need.

Cut with scissors to the dimensions.

Use spray glue. Read well the instructions on the one you get. With the LePage and Nashua, you need to spray on both surfaces (the bubble wrap and the wall) and let it sit for 2-5 minutes before glueing it together.

Place the bubble wrap to the appropriate surface on the walls of the van. Apply pressure everywhere to make sure it is well glued.

For the smaller sections (between the ribs), we made sure to cut out little wings to fit on the ribs and behind the ribs when possible. For the even smaller sections (in the ribs), we were sometimes able to add a rectangle of bubble wrap without glueing it in place. The fiber glass insulation will hold it in place.

Step 7: The Walls: Second Layer Is the Fiberglass Insulation

SAFETY NOTE: Use gloves and masks for this part of the work. Fiberglass insulation is not the nicest material to work with, however we got ours for free, so we did not complain.

Approximate the size of the pieces you need to cover each piece of bubble wrap.

Use scissors to cut to size.

In the small sections surrounded by ribs, shove the insulation into place.The ribs should be enough to hold it in place. Don't compact the insulation too much, as it is the little air parts between the fiberglass that creates the insulation.

For the larger sections, we used tape to hold the insulation in place. Since we know that there will be the vapor barrier and the final paneling, this is a good enough temporary solution!

Step 8: The Walls: Foam Insulation in the Beams

SAFETY NOTE: Use gloves and goggles for this part, as this stuff is really sticky on the fingers and would definitely not be good to have in your eyes.

There are still gaps behind some of the beams that are not possible to attain with bubble wrap and fiberglass insulation. For those, we used foam insulation in a spray can. We read only later that you are supposed to fill in only to 50% of the gap with the foam, since it will expand afterwards... So we had to cut out the excess!

Step 9: The Walls: Third Layer Is the Vapor Barrier

The final step is to add the vapor barrier to seal everything. The goal here is to have no air coming from the van to the fiberglass insulation.

Start by cutting an approximately good size piece of plastic for each section. For sections, we used the large beams already on the walls to dictate where we were going to separate the sections.

For each section, start by using tuck tape on the top part of the piece to secure it in place.

Then make sure to cut out space for the wheel for the bottom piece. Make sure the size is ok all around.

Then tape down the bottom, and finish with the sides.

We had some more delicate cutting outs to do around the ceiling studs, and around the back anchor for the door. With some patience and good scissors, everything can be sealed out properly!

YOU ARE NOW DONE! The insulation for the van is complete. If you want a super extra good job, you can also add some insulation in the panels of the doors. We did not get to this part yet. You can also insulate around the wheels, but this has to be done in conjuncture with whatever you want to build around the wheels.

Once this is done, the next step will be to cover the insulation with a 'pretty' finish so that it is nice and welcoming to live in the van. Some people use thin plywood, some use plywood covered with fabric or rug. We are thinking of using thin cedar tongue-in-groove slats for a very nice finish. This will come in the next instructables tutorial!

As I said in the intro, this is the first van conversion we are working on. We do not claim that this is the best way to insulate the interior of a van, however we believe that we have done a thorough research of online resources and what we present here is a nice summary of the best options we have seen out there, considering our budget, our skills, our schedule, and our future use for the van (winter adventures!). We welcome all comments or questions, since we are curious to see how others have done it.

I didnt go through all the comments but i was wondering how you did in cold temperatures. Which way do you heat in winter and whats the lowest temperature you go without being uncomfortable. Im looking to wintetrise my van but in quebec the winters can be pretty harsh with temperature going easily under -30°c.

I'm just going to start insulating my Transit van, which brings me to this site. I live on Vancouver Island and of course the climate is wet in winter. There seems to be no definitive answer regarding vapour barrier. One thing I will caution though, is that fibreglas insulation definitely will harbour mold. I ripped out a bathroom for a friend and the yellow fibreglas insulation was more black than yellow. This was below grade against a concrete wall. I had thought about using fibreglas in my van but the possibility of mold is giving me second thoughts. I have an enclosed motorcycle trailer and it gets moldy every winter. Some people use styrofoam, which provides great R value per inch as opposed to fibreglas or Reflectix. Apparently Reflectix claims an R value of 11, which can only be achieved if it is installed in the middle of a 2x4 studded wall with 3/4" plywood on either side (so now you have the R value of about 3" airspace sandwiched between two 3/4" layers of plywood. The Reflectix by itself apparently only has an R value of around 1. The downside of installing styrofoam is that it may squeak and it's difficult to seal up gaps (unless you're willing to use spray foam). I'm still considering using spray foam for the whole thing, but it's a little more permanent than I'd like and it's pretty hard to control the depth during application. Bottom line: I'm still on the fence about how I'm going to do this.

So, we are also still not sure what the best way to do this is. However, after living in the van (over weekends and for trips), the one thing that I think makes a difference is to have good ventilation in the van. We have a ceiling fan that we always keep open at night (even in winter), and we have a side window in the sliding door that we also keep open most of the time. When the two are open, it helps with circulating the air. However, there are winter mornings where we definitely see all the moisture in the van... Let us know what you decide to do!

Hi! yes, we are still here! The duck tape was not wonderful on the ceiling. So at the moment, the cedar panels that are nailed to wood ribs (which are screwed to the ceiling) are holding the foam on the ceiling. It is tight enough that it is staying there for now.

Hi I'm about to start building a van to travel around BC for the next yr. With the level of insulation you used how warm has the van been in the harsh winters? Was there enough? I'm not planning on using a heater. cheers

hello! Thank you for the write-up! We have the same van (but 2006) and the same insulation materials (we're just starting!). The only other thing we are considering for insulation is a sound deadener like fat mat rattletrap to start. Is your van plenty quiet or would you recommend going with that extra layer to block out more noise?

I have question after question dont i? A big debate going on inside my head right now is weather or not to install a vapor barrier i do live in a moist humid climate so a vapor barrier sounds smart but wont that just stop the insulation from breathing or releasing the moister wont the moisture just get trapped in the walls and cause the metal walls of the van to rust Im planning on using wool insulation what do you all think about that

This is a tricky question. I am not an expert at all, but from all the documentation I read about, I think it is better to have the vapor barrier and to make it as air tight as possible to keep the moisture out.

I've been mulling this question for a while too, and have tangential experience with building envelopes from my career (mech engineer). The issue with using a vapor barrier is that you are installing a SECOND vapor barrier. The first vapor barrier is the metal wall on the outside of the van. No vapor is going out that way (minus any odd air passages that certainly do exist - but not in enough quantity for the insulation to breathe well). If you install a vapor barrier you're effectively trapping any small amount of moisture that does make its way in there, and then the insulation will stay wet for long periods of time.

I've addressed this by not installing a vapor barrier, and by using fiberglass insulation. I'm looking to source some light fabric that I could put where you put the vapor barrier to help avoid any small insulation fragments making their way into the cabin (seems unlikely, but I don't want to risk getting nasty fiberglass bits into the breathing space) but would allow decent moisture transport. Not sure what I'm using yet..... you could use denimn insulation instead, but those products have issues when they get wet. Advantage of fiberglass is it'll never mold up.

thanks for all the ideas though - been digging using your writeups as launching points for our van!

I recently purchased a 1997 Toyota Hiace. I am wanting to convert it into a camper.I'm from Australia and I am hoping you can recommend the right insulation to use? It will be going on Metal and I need the right insulation for hot and cold climates as well as anti-moisture.

Thank-you so much for sharing all this information. Hope you can help.

Thanks! The metallic bubble wrap could probably do. However, I think that part of the role of the insulation (and certainly of the vapor barrier) is to help prevent the walls from rusting over time. I think you could also do a thin layer of spray insulation?

Thanks for the great comments! Well... there are no real plans, in the design sense of things. But there is a tutorial with dimensions: https://www.instructables.com/id/Storage-platform-for-the-back-of-your-Sprinter-van/ Have you seen this one already?

It also depends quite a bit on the exact size of your van. Do you also have a sprinter?